Indications

The usual indications for a bypass are obstruction by a benign or a malignant stricture. Benign strictures are particularly likely to occur in the distal bile duct as a result of stones, or chronic pancreatitis. Benign strictures in the middle of the of the common duct, up to and including the bifurcation can also be caused by stones, parasitic infestations, autoimmune inflammation of the ducts (e.g., sclerosing cholangitis), congenital problems (e.g., Caroli's disease), or even trauma. However, the most common reason is iatrogenic: the most notorious of these in modern times being an operative injury during laparoscopic cholecystectomy. The injury may occur by transaction, inadvertent clip placement, cauterization or indirectly by devascularization of the duct. Because the blood supply to the mid-bile duct is axial (Fig. 3), it is relatively susceptible to devascularization. The injury may or may not be recognized at the original surgery. If it is recognized and repaired simply by reapproximating the divided duct, the repair often fails; resulting either in bile leakage, which occurs early, or stricture formation, which occurs several months to years after the surgery. Rarely, late bile duct stricture may develop because of neuroma formation around the cystic duct stump following an apparently uncomplicated operation (1). In addition to laparoscopic surgery, several other operations and therapeutic maneuvers can result in bile duct injury with subsequent benign stricture as a complication. These include misadventures during operations on the common bile duct, hepatic resections, duodenal and pancreatic operations, and gastric operations for peptic ulcer disease. Endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy can damage the bile duct as well as infusions of chemotherapy into the hepatic artery, and misadventures during percutaneous trans-hepatic procedures (e.g., stent placements, cholangiograms, biopsies, and so on). In the absence of an obvious cause for a bile duct stricture, it can be difficult to distinguish benign and malignant strictures, and this uncertainty often animates therapeutic choices.

Malignant obstructions or strictures can also occur at any level in the biliary tree, but most commonly involve the distal end as a result of a ductal adenocarcinoma of the head of the pancreas. Adenocarcinoma of the ampulla of Vater, the duodenum, and even the bile duct (cholangiocarcinoma) all occur in the same region and can be virtually impossible to distinguish from cancer of the head of the pancreas preoperatively. When resectable, these tumors are all handled by a Whipple procedure (see Chapter 20). Primary cholangiocarcinoma arising in the mid-bile duct is also occasionally treatable with a segmental resection of the bile duct, and this should be done if it is feasible. More commonly, proximal cholangiocarcinomas involve the bifurcation of the bile ducts (Klatskin's tumors). To achieve clear margins for these tumors often involves hepatic parenchymal resection too as was aforementioned. The bile duct may finally be obstructed by malignant ingrowths from other adjacent organs. This happens most commonly with locally advanced carcinoma of the gallbladder, but can occur from nodal metastases from gastric or colon cancer, or even lymphomas involving the portal lymph nodes in the hepatoduodenal ligament.

Another indication for biliary-enteric procedures is biliary atresia in infants. These infants may have only vestigal remnants of their biliary tree. The ideal situation for a biliary-enteric anastomosis is one in which the intrahepatic ducts are normal and only the extrahepatic ducts are atretic. When there are no obvious dilated intrahepatic ducts and the condition is recognized before liver failure and cirrhosis supervene, the infant may undergo a procedure called the Kasai portoenterostomy. This operation also involves reconstruction of the extrahepatic biliary tree with a Roux-Y limb up to the hepatic hilum where the intrahepatic ducts are supposed to be. The area where the atretic ducts are above the portal vein bifurcation is cored out with hepatic parenchyma, and the jejunum is sewn to the liver there in anticipation of bile drainage from microscopic bile ductules. Success depends upon performing this operation soon enough to avoid the complications of liver failure, and on how much of the biliary tree is atretic. If there are no intrahepatic ducts at all, the Kasai procedure will fail and liver transplant must be performed then. After one of these operations, the effluent into the roux limb is carefully monitored for bile because a remarkable number (40%) of these infants will survive if bile flow develops and their jaundice clears. The incidence of repetitive episodes cholangitis in survivors is quite high and surviving children must be watched for the later development of cirrhosis and its attendant complications. Liver transplant can salvage these patients even after a Kasai portoenterostomy (2,3).

Finally, patients may undergo either a bypass or reconstruction after a resection of a type 1 choledochal cyst. In this congenital biliary abnormality, the extrahepatic bile duct balloons out. Patients suffer repetitive attacks of cholangitis and are subsequently at higher risk for the development of cholangiocarcinoma in the cyst. Because it more effectively prevents subsequent attacks of cholangitis in this condition, and because of the threat of malignancy, resection of the cyst and reconstruction with a Roux-Y limb is preferred over simple bypass. During resection the surgeon must be particularly aware of a frequent anomaly: high entry of the pancreatic duct into the bile duct. If this duct is inadvertently oversewn during the closure of the distal duct, particularly severe pancreatitis may be precipitated.

Common bile duct

Common bile duct

Anastomosis

Anastomosis

Common bile duct

Common bile duct

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